Resynchronisation of the Biological Clock Using Exposure to Low Oxygen Levels in Humans: An Exploratory Study
Abstract
Exposure to reduced oxygen levels occurs in several real-world contexts, such as during air travel or altitude exposure, and emerging evidence suggests that hypoxia may interact with molecular pathways involved in circadian regulation. This exploratory study investigated the effects of normobaric hypoxia on circadian phase shifting in humans, compared to luminotherapy combined with exogenous melatonin. Using a randomised crossover design, 11 healthy adults (6 men, 5 women; mean age 23.3 ± 1.9 years) completed one baseline and two 48-h experimental conditions. The baseline established individual circadian markers. Both experimental conditions simulated a 4-h phase advance. In the hypoxia condition, participants were exposed to reduced oxygen levels (inspired oxygen fraction of 12%) for 2 h, beginning 2 h after habitual wake time. In the luminotherapy and melatonin condition, participants received three-hour morning light therapy (500 nm, 506 lx) at the same time point, combined with 5 mg melatonin administered 6 h before bedtime. Salivary melatonin was collected across conditions to determine dim-light melatonin onset (DLMO). Both conditions produced earlier melatonin onset compared to baseline. The luminotherapy and melatonin condition resulted in a significant phase advance of approximately 78 min. The hypoxia condition produced an average phase advance of approximately 35 min, which was not statistically significant. The present findings do not allow us to determine…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 11 participants or records.
Read the paper
Related studies
- A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials Evaluating the Evidence Base of Melatonin, Light Exposure, Exercise, and Complementary and Alternative Medicine for Patients with Insomnia Disorder
- Use of Melatonin and/on Ramelteon for the Treatment of Insomnia in Older Adults: A Systematic Review and Meta-Analysis
- Influence of evening light exposure on polysomnographically assessed night-time sleep: A systematic review with meta-analysis
- Use of melatonin in children and adolescents with idiopathic chronic insomnia: a systematic review, meta-analysis, and clinical recommendation
- Significant potential of melatonin therapy in Parkinson’s disease – a meta-analysis of randomized controlled trials
- Meta-Analysis: Melatonin for the Treatment of Primary Sleep Disorders
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.